The invention concerns an apparatus for cutting free the flank bones of beheaded, slaughtered fish having open abdominal cavities which are transported on transport saddles, comprising an upper bone guide, a lower bone guide and a separating unit for detaching fish fillets from the flank bones, wherein the separating unit includes a separating means with corresponding counter support and can be moved out of a standby position into a working position and vice versa. Furthermore the invention concerns a filleting machine for filleting beheaded, slaughtered fish having open abdominal cavities, comprising dorsal knives for exposing the back spokes as far as the backbone, abdominal knives for exposing the belly spokes in the tail region as far as the backbone, an apparatus for cutting the flank bones free, separating knives for separating the fillets in the tail region from the backbone while cutting through the web left round the backbone by abdominal and dorsal knives, an endless conveyor for transport of the fish tail first, and a number of fish saddles arranged on the conveyor for reliably receiving the fish in their abdominal cavities.
Such apparatuses and filleting machines are used in the fish-processing industry to fillet fish automatically, in particular the salmon species. An essential working step in the automated filleting of fish is detaching the fillets from the flank bones, that is, the rib arches, which extend on both sides of the backbone. In the process the fish are transported by means of the transport saddles to the individual processing tools, inter alia the apparatus for cutting the flank bones free. The upper and lower bone guides serve to hold and guide the fish in the optimum processing position on the transport saddle. The separating unit is usually arranged on both sides of the fish to be processed, so that the fillets can be detached from the flank bones in parallel or with a time delay.
Detachment of the fillets from the flank bones takes place in the state of the art, which is formed e.g. by WO 02/03807 A1, by means of a scraping tool. In other words, the apparatus for cutting the flank bones free is formed by a scraping tool which is composed of scraping knives and scraping knife counter supports. Both the scraping knives and the scraping knife counter supports are fixed and, in addition to the capacity for vertical displacement, can also be swung out laterally. This known apparatus and hence also a filleting machine with such an apparatus have the drawback, however, that the cut surface is raw from the scraping detachment. Furthermore the possibilities of cutting guides are limited by the fixed scraping knives or scraping knife counter supports, so that the first flank bones sometimes remain in the fillet. This results in increased requirements for subsequent processing, leading to additional costs.